Heating of fluids



Oct. 13, 1953 M. w. BARNES HEATING OF FLUIDS Filed Oct. 24, 1950 e-oe-oo-ee-ee-e W 07''7Z y I Patented Oct. 13,1953

. UNITED sures PATENT emce- Marlon W. Universal Barnes, Wilmette, Ill.,- minor to Oil Products Company, Chicago, Ill.)

a corporation of Delaware Application October--24, 1950, Serial No. raises 4 Claims. (01. 122-2641 This invention relates to an improved fluid heater construction and arrangement suitable to eifect the heating of a plurality ofseparate fluid streams, and more particularly to a construction having a fluid conduit arrangement which permits controlled and substantially independent heating of each of the separate fluid streams.

The present heater is a combination radiation and convection heater of the general type used in the oil refining industry, and known as the center wall updraft heater having a longitudinal center wall dividing the lower portion of the heater into separate longitudinal combustion and radiant heating zones. Burners are arranged to impart flame and hot combustion gases substantially along the full length of the center wall and thus produce radiant heating for a plurality of fluid conduits which are in turnplaced adjacent each of the side walls of the heating chamber. The resulting combustion or flue gases are passed upwardly through the heating chamber into a reduced cross-sectional area upper heating zone, which in turn has additional fluid conduits placed relatively close together forming a tube bank which is subjected to convection heating from the hot gases prior to their discharge into a breaching and stack.

Various arrangements of fluid conduits or tubes have been utilized in modifications ofthe center wall up-draft type of heater, with resulting advantages obtained. It is a principal object and feature of the present invention to provide an improved arrangement of tubes for fluid flow,

whereby a plurality of fluid streams may be passed through the heater in a similar pattern of flow, but in a manner such that independent heating of the separate streams or coils may be effected.

It is also an object and feature of the improved arrangement to provide separate radiantly heated coils or tube banks adjacent each side wall of the heating chamber, in an end to end arrangement, and the positioning of burner in a longitudinal row each side of the center wall members such that by adjustment of the various burners there maybe different heating effected in each of the different coils at the ends of the heater.

In one embodiment, the improved apparatus for heating a plurality of fluid streams, comprises in combination, a furnace chamber having a floor and side and end walls defining the lower portion thereof, a longitudinal center wall dividing the lower portion of the heater into separate radiant heating zones, inwardly sloping side wallsections extending from above their tion heating zone, a plurality of horizontally positioned fluid conduits disposed adjacent each of the sloping wall sections, and a plurality of horizontally positioned radiantly heated fluid conduits disposed adjacent each of the side wall sections in each of the separate radiant heating zones, one portion of the conduits in the convection heating zone connected in series and having the lowermost conduit thereof connecting to a portion of the conduits disposed along one of the slopingwalls and with a portion of conduits adjacent the lower side wall, with all of the latter connected in series, another portion of the conduits within the upper convection heating zone connected in series and the lowermost conduit thereof connecting to a second portion of conduitsdisposed adjacent the sloping side wall and lower side wall, with each of the latter connected in series, another portion of conduits in the convection heating zone connected in series, with the lowermost conduit thereof connecting to a portion of the conduits disposed along the other of the sloping walls of the heater and a portion of the fluid conduits adjacent the lower side wall of the other side of said heater, with each of the latter tubes being connected in series, the remaining portion of the fluid conduits in'the convection heating zone are connected in series and the lowermost conduit thereof connects with the remaining portion of the fluid conduits adjacent the last mentioned sloping wall and lower side wall of the heating chamber, with the latter mentioned conduits connected in series, whereby separate or independent fluid streams may be passed through said heating chamber and subjected to different heats absorptions while passing in similar flow paths and arrangements.

In a preferable arrangement, there are two separate coils or sets of fluid conduits comprising serially connected horizontal tubes adjacent each of the sloping walls and lower side walls of the chamber, with each coil or tube bank on each side extending approximately half the coils are in an end to end relationship and each subjected to radiant heating from the center wall.

This arrangement permits independent or controlled heating of the different coils, by means of firing the burners against the center wall to a different degree, in order to in turn eflect differences of radiant heating from the wall within the different ends of the heating chamber and in addition provides means for splitting one fluid stream into a plurality of streams having a simi-- lar flow pattern, or alternatively, passing different fluid streams through one heating chamber and subjecting them to similar heating conditions. It may be advantageous to split a single fluid stream into separate streams in order to reduce pressure drop, which might be high where the single stream is required to pass through a large number of relatively small fluid conduits in the heating zone.

The improved heater arrangement and construction as well as additional advantages and features will be more apparent upon reference to the accompanying drawing and the following description thereof.

Figure 1 of the drawing is a diagrammatic sectional elevational view of a heater embodying the features of the present invention.

Figures 2 and 3 of the drawing indicate diagrammatically portions of the fluid conduit arrangement, as indicated by the line 2-2 and the line 3-3 in Figure l of the drawing.

Figure 4 indicates diagrammatically a modifled tube and coil arrangement for the heater permitting the inlets and outlets for each separate coil to be at but one end of the heater.

Figures 5 and 6 of the drawing are diagrammatic side elevational views of portions of the fluid conduit arrangement, as indicated by the lines 5-5 and 66 in Figure .4 of the drawing.

Referring now to the drawing, the up-draft heater shown has lower side walls I and I, sloping or hip walls 2 and 2', and upper vertical walls 3 and 3, which together with asuitable refractory floors 4 and 4' and end walls provide an enclosed furnace chamber. The lower portion of the heater chamber is divided by a longitudinal center wall 5, extending for substantially the full length of the heating chamber, preferably resting on a center portion of the heater foundation 6, and provides a center wall up-draft form of heater. Separate combustion and radiant heating zones are formed on each side of the center wall 5, indicated as I and I, and above the center wall between the more closely spaced upper side wall 3 and, 3' is a convection heating zone 8.

Combustible fuel and air are supplied to the heater by way of burners 9 and supply lines III, with each of the burners 9 firing through suitable ports or burner blocks M each side of the lower portion of the center wall 5. The burners 9 and accompanying burner blocks II are spaced longitudinally along each side of the furnace chamber for substantially the full length thereof. An alternative arrangement, for oil or other type of burners may direct flame through suitable burner blocks 12 which are spaced longitudinally along the lower side walls I and i just above the floor of the furnace. In either case, flames and hot combustion gases are directed against the side walls of the center wall 5 in a manner to heat it to a highly radiant condition. Thus, fluid heating conduits adjacent each side wall of the heating chamber are subjected to radiant heating, while resulting hot combustion gases pass upwardly between the sloping hip walls land 2' and between the upper vertical walls 3 and 3', which define the convection heating section 8, to provide convection heating for a plurality of fluid conduits in a bank therein. Substantially cooled flue gases pass from the upper end of the heating chamber into a breaching or stack [3, from which they may be subsequently passed to the atmosphere. The side walls, end walls, floor and dividing center wall are preferably constructed of suitable refractory material, which may be either of poured monolithic construction, or refractory block or tile, which in turn may or may not be of the suspended tile type of construction. Usually the center wall 5 is of built up construction and rests on the portion of the heater foundation, as indicated in the present drawing.

In this particular embodiment, a plurality of tubes or fluid conduits are maintained horizontally and in vertically spaced rows comprising tube bank 14. Further, the tubes or fluid conduits are in staggered arrangement with four tubes to each horizontal row, and the horizontal spacing such that the tubes substantially traverse the entire cross-sectional area of the convection heating zone 8. In a single horizontal row directly below the convection heating zone 8 are shock tubes l6, l5, l5 and it, which in turn connect with the hip tubes of the heater in accordance with the present invention. Along the sloping or hip walls 2 and 2, are two sets of fluid conduits or tubular coils. The near banks of coils or tubes being indicated as H and I1 adjacent each of the respective hip walls 2 and 2'.

In a similar manner, two banks of conduits or tubular coils are positioned. adjacent each of the respective side walls I and I, the near tubular banks being indicated in Figure 1 of the drawing as l8 and 18 respectively. The fluid conduits in the heater which are along the near end thereof, in Figure l, and indicated as being in tube banks 11, IT and I8 and I8, extend for only about one half the length of the interior of the furnace chamber, so that similar banks or coils of tubes may be placed adjacent the sloping and side walls of the heater within the far end thereof, with all of the tubes being in horizontal position and in a substantially end to end relationship with respect to the tubular conduits shown. As may be better shown within Figure 2 of the drawing, a plurality of conduits or tubes l9 are positioned adjacent the sloping or hip wall 2', beyond the tubular bank I1. and within the far end portion of the heater chamber. Similarly, conduits are arranged adjacent the side wall I within the far end of the heating chamber and radiant heating zone I, and beyond the plurality of fluid conduits l8 which are shown in Figure l of the drawing. Figure 3 of the drawing shows more clearly the positioning of fluid conduits 20' which are in the tube bank or coil in the far end of the heating chamber beyond the tub bank 18'.

Fluid flow in one specific embodiment, as indicated, is from the upper end of the heating chamber downwardly through the tubes to the lower end of the chamber. One fluid stream enters by way of inlet A to a conduit in the uppermost row of the tube bank H and passes downwardly through a staggered vertical row of tubes connected in series flow by suitable return bend fittings, or U-shaped bends which are welded to the ends of the tubes. Asmay be better shown in Figure 2 of the drawing, the fluid stream A passes from the lowermost oi the convection bank of tubes into the far end of shock tube- It. and

subsequently from the latter into the "series of shorter tubes H, which in tum-are connected. in

, series by suitable return bends or U-shaped flt- The stream continues in a-series flow from the lowermost tube il' into the upper end of the series connected tubes ll; which are also tings.

within the near end 0! the heating chamber as indicated in Figure 3 of the drawing. The fluid 10 is exposedto high temperature radiant heat within-the radiant heating zone 'I' and tube bank it, such that a highly heated fluid stream may be withdrawn from the lower end of the tube bank It by way of outlet A. p

In a similar manner, another fluid stream may enter, by way of inlet tube 3, into a second substantially staggered vertical row of tubes in the convection heating bank It. Each of the tubular members being connected in series flow and :extending substantially the full lengthot the heat-- ing chamber, thus providing a continuous series flow of the stream through the convection heati ing zone 8 and to the near end of a shock tube IS, the latter tube being somewhat longer than' the adjacent tube It and having a special long U-shaped fitting 2| which is adapted to reach the far end of the uppermost short tube IS in the coil or bank thereof which is disposed in the far end of the heating chamber beyond the nearer coil of tubes l'l'. Each of thefluid conduits in the coil l9, as well as the fluid conduits of the coil or bank 20 are connected in series, such that the fluid stream continues in a series flow downwardly through each tubular member of the bank to the lower end of the heating zone 1' and may be discharged at a high temperature by way of outlet B, which is indicated in Iiigure 3 of the drawing.

Additional fluid streams are heated within an upper convection tube bank and coils which are ward from the latter through a side wall tube coil to an outlet C at the lower end of the radiant heating section I. A fourth fluid stream may enter by way of an upper inlet D to an upper convection tube so that the fluid stream may pass in series flow through the series connected remaining portion of the convection heating bank M, which are arranged in staggered formation adjacent the side wall 3. The stream continues in series flow from the lower end of the convection heating section 8 into the long shock tube l6 at the far end thereof, and subsequently passes into the tube bank i1 and tube bank In. Each of the fluid conduits of the latter banks or coils having shorter'tubes connected in seriesso that a single continuous stream passes downwardly subject to high temperature radiant heating within zone 1, and permitting a high temperature stream to be withdrawn by way of the lowermost tube and outlet D.

The present embodiment indicates a downward flow for each of the fluid streams, so that the fluid is subjected to mild heating within the convection heating zone 8 and subsequently to a combination of convection and radiant heating within the hip sections, and subsequently to high temperature 7 accuse of the furnace chamber. However, it-should be noted that the present. improved tubular ar- 1 rangement and flow is not confined to this downward flow only. for obviously inlets maybe provided at the lower end or the heating chamber,

permittingan upward flow through each of the coils and to the convection heating zone where soaking heat may be provided after a quickhigh temperature heating within the radiant heating sections. a

The present embodiment shows only four tubular conduits within each horizontal row in the convectionheating zone and tour coils or tube bankswithin the lower portion of the heating chamber. .as provided by the two sets of series connected conduits on each side 01' the furnace chamber, however, additional tubes may be placed within the convection heating zone and additional heating coils or banks may be placed in an end to end arrangement along or adjacent each of the side walls of the chamber, such that three or more banks of series connected tubes are adjacent each side wall of the unit.

Where it is desired to heat all of the fluid streams. to substantially equal temperatures, the burners 9 are adjusted to provide substantially equal heating of the center wall I along each side thereof and substantially uniform temperatures within the respective radiant heating zones 1 and 1'. However, in accordance with the particular advantage of the present arrangement, difierent heating conditions may be provided for each of the fluid streams as they pass downwardly through the heating chamber. In other words, the burners 9 may be adjusted to provide a different degree of heating against the center wall at one end of one radiant heating section as compared to the other end thereof, and resulting different heat absorptions or B. t. u. inputs may be provided tor each of the separate fluid streams v which pass through the separate and independent tubular coils of the heating chamber. This is of particular advantage where difierent fluid mediums are being heated within a single heating chamber, permitting different, heating conditions for independent fluid streams without the necessity of building more than one heating chamber or structure and thus eiiecting very desirable savings in total expenditure for any processing plant. Further, it may be desirable to split a .single large quantity fluid stream into a plurality that all streams leave at substantially equivalent temperatures and heat absorptions.

Referring now to Figure 4 of the drawing, there is indicated another specific embodiment. providing separate streams or fluid flow downwardly through the heating chamber, and means for serially connecting tubes within the convection bank of tubes and the tube banks or coils placed adjacent the sloping hip walls and the vertical side walls.. The advantage of this embodiment is that the inlet streams may all enter through a header, such as H, at one end of the heater, and the two coils which are placed in an end to end arrangement adjacent each side wall of the heating chamber may be arranged so that the outlets are at the same end of the heater. A separate fluid stream, or as shown, a portion of a fluid stream enters from header H into an upper tube 22 and subsequently passes in series flow downwardly through a staggered vertical row of tubes in the convection section 8 to a shock tube 24. The shock tube 24 connects at the far end of the heating chamber by means of a U-bend with another long tube 25, and the latter subsequently connects in series with the bank of tubes 21 which are disposed adjacent the sloping wall in the near end of the heating chamber, as indicated in Figure of the drawing. In accordance with this arrangement, all of the shorter tubes comprising the series connected coil 21 and the series connected coil 28, which is adjacent the vertical -wall, provide high temperature radiant heating for the fluid stream which passes in a series flow down through the heating chamber within the near end of the furnace. The lovermost tube 28 discharges by way of outlet H at the near end of the furnace chamber, which in this instance is at the same'end as the inlet header H.

Another separate fluid stream passes from the inlet header H into an upper conduit 23 in the convection section of the heater and downwardly in a staggered vertical row of convection tubes into a shock tube 26, which extends substantially the full length of the heating chamber .as indicated in Figures 5 of the drawing. The fluid flow through the convection section is a series flow with suitable U-bends, or return bend fittings,

connecting the tubes in the desired series connectedflow. The series flow continues from the far end of conduit 26 by way of a long special U-bend fitting 30, which in turn connects with the far end of the uppermost tube 21A, which in turn is the uppermost tube of the coil 21A disposed at the far end of the furnace chamber in an end to end relationship with the near end of the furnace tube coil 21. The series flow continues from the lowermost tube 21A into the series connected coil of tubes 28A, which as indicated in Figure 6, are positioned in an end to end relationship with the near end tubes 28, along the vertical side wall of the furnace chamber. The fluid in the latter coils is subjected to high temperature radiant heating within tube banks 21A and 28A, with the fluid flowing from the lowermost of the shorter tubes 28A in series flow into a long tube 29, which is indicated in Figure 6, to bring the fluid stream to the near end of the heating chamber and to the outlet H.

Similar flows may be provided through other serially connected tubes in the other half of the heating chamber, which are not shown on the present drawing, but may be opposite hand to the view shown in Figure 4.

It may also be pointed out in connection with this last described embodiment, that entirely separate inlets may be provided for each of the fluid flows through the heating chamber and the coils need not be connected to a header at the inlet end or at the outlet ends, which provides for splitting a single fluid stream into a plurality of separate streams passing throughthe heating chamber. Still further, where desired, an upward flow may be arranged with the inlets to the heating coils and tubes placed at the lower end of the furnace chamber so that the separate streams pass in series flow upwardly through the heater to the convection bank and outwardly from the latter to separate outlet conduits, or alternatively to a common header such as H.

I claim as my invention:

1. Heating apparatus for effecting the'heating of a plurality of fluid streams and comprising in combination, a furnace chamber having a floor and side and end walls defining the lower portion thereof, a longitudinal center wall dividing said lower portion into separate radiant heating zones, inwardly sloping side wall sections extending from above said lower portion of said chamber and connecting with relatively close spaced upper side walls, the latter defining an upper convection heating zone, a plurality of burner means spaced along and directed towards each side of said center wall providing radiant heating within each of said radiant heating zones and resulting hot combustion gases effecting convection heating within said upper convection heating zone, a plurality of rows of horizontally positioned fluid conduits arranged in staggered formation within said upper convection heating zone, said plurality of fluid conduits extending substantially the full length of said heating apparatus, two separate banks of shorter fluid conduits horizontally positioned in a substantially end to end relationship adjacent each sloping wall and each vertical side wall of each side of said furnace chamber, one substantially vertical portion of said staggered fluid conduits within said convection heating zone connected in series and the lowermost conduit thereof connecting to one of said separate serially connected and shorter fluid conduit banks adjacent one of said sloping and vertical side walls in the lower portion of said chamher, a second substantially vertical portion of said staggered conduits with said convection heating zone connected in series, with the lowermost conduit thereof connecting to the second of the separate tube banks adjacent aforesaid sloping and side wall of said furnace chamber, a third substantially vertical portion of said staggered conduits within said convection heating zone connected in series and having the lowermost conduit thereof connecting to one of said separate shorter tube banks serially connected and positioned adjacent the other of said sloping and side walls of said furnace chamber, and the remaining portion of said staggered conduits in said convection heating zone connected in'series with the lowermost tube thereof connecting with the remaining bank of shorter fluid conduits which are serially connected and positioned adjacent the last mentioned sloping and side wall of said furnace chamber, whereby four separate fluid streams may be heated as they pass in series flow downwardly through a plurality of series connected horizontally positioned fluid conduits to the lower radiantly heated portion of said furnace chamber.

2. The heating apparatus of claim 1 further characterized in that each of said plurality of shorter fluid conduits positioned adjacent each of the sloping and lower side walls of said furnace chamber are in series connected banks of tubes which extend for approximately one-half the length of the interior of said chamber.

,3. The heating apparatus of claim 1 further characterized'in that said plurality of spaced burner means are adjustable and provide variable heating within the ends of said chamber and said radiant heating zones on each side of said center wall.

4. The heating apparatus of claim 3 still further characterized in that the inlets to each of the separate fluid streams are connected into the uppermost conduit of each of the portions of" 10 References Cited in the file of this patent UNITED STATES PATENTS Number Name Date Coghill June 21, 1938 Mekler Feb. 21, 1939 Nash et a1 Jan. 21, 1941 Barnes Oct. 31, 1944 Schutt Sept. 26, 1950 

